On Mon, 20 Aug 2018 at 22:11, Alexander Medvednikov via gtk-list <[hidden email]> wrote:
GTK draws things with Cairo, and if the graphics driver is installed, Cairo uses the OpenGL backend. Otherwise it uses software rendering via xlib.
Is this correct?
GTK does not use the GL backend of Cairo, only the Xlib surfaces (on X11) or the image surfaces (on Wayland), as the GL backend of Cairo is mostly experimental.
If Glamor is enabled, then the X server will use GL as an acceleration architecture, but that has no particular bearing on GTK, as Glamor accelerates the X primitives, and GTK uses client side rendering.
This, of course applies to GTK+ 2.x and 3.x; in 4.0, GTK+ will be able to use Vulkan or OpenGL as a rendering API, and only use Cairo as a fallback, or if widgets explicitly decide to use Cairo surfaces to render their contents.